The invention relates generally to a mobile support structure and more particularly to a support structure for a rig which is capable of adapting to uneven terrain. Support structures of the type to which the present invention relates usually include four support bearing members which bear upon the terrain and which are arranged at least approximately in the corners of a rectangle, with the bearing members being located in a common reference plane when the terrain is flat.
Support structures of this type are used, for example, as supporting frames for construction rigs such as rotary cranes, excavators and the like. When used in this connection, there arises the problem of achieving simultaneous contact with the ground with all four support bearing members when the terrain is not even without reducing the stability of the rig and its load capacity. Prior art measures for solving this problem have heretofore been suggested, for example in German Auslegeschrift No. 1,171,594. However, measures of this type have been found to be unsatisfactory.
Other examples of prior art devices may be found in the following German patent publications: DE-AS No. 1,026,498; DE-OS No. 2,548,381; and DE-GM No. 1,821,433.
The invention is directed toward the task of designing a support structure of the type described above which is capable of operation on uneven ground formations and which is as rigid as possible against forces introduced from the supported rig.